<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>观察者模式</title>
</head>
<body>
    
</body>
</html>
<script>
    //发布者-目标
    class Dep {
        constructor(){
            //记录所有订阅者
            this.subs = []
        }
        //添加订阅者
        addSub(sub){
            if (sub && sub.update){
                this.subs.push(sub)
            }
        }
        //发布通知
        notify(){
            this.subs.forEach(sub=>{
                sub.update()
            })
        }
    }
    //观察者-订阅者
    class Watchor {
        update() {
            console.log('update')
        }
    }

    //测试
    let dep = new Dep()
    let watchor = new Watchor()
    dep.addSub(watchor)
    dep.notify()
</script>